The invention relates to a polyolefin functional master batch, a preparation method thereof and use thereof. The functional master batch is prepared by blending a polyolefine resin, a guazatine oligomer, an olefin monomer, an initiator and the like and by a method of solvent graft, solid phase graft or melt graft and has a structural formula below, wherein in the formula, R represents the guazatine oligomer grafted to molecular chains of the polyolefin, and T may be hydrogen, chlorine, methyl, or phenyl. Compared with the prior art, by blending the functional master batch prepared by the invention with the corresponding polyolefin, various products, including fibers, thin films, water pipes and other plastic products, which have high antimicrobial performance and long-lasting effect and is safe and nontoxic to human bodies can be manufactured; and meanwhile, the acidic dye and disperse dye uptake of polyolefin fibers can be improved greatly, and the surface polarity, antistatic performance and paint film adhesion of polyolefin materials can be improved.